DESCRIPTION (after the Application): The proposed research is a four-year study of 600 ischemic stroke patients which is designed to evaluate the utility of new neuroimaging technology in the acute setting to improve prediction of stroke outcome. Currently, data from the standard imaging study, a non-contrast computed tomography (CT) scan of the brain, add little to clinical measures of stroke severity. In the majority of ischemic stroke cases, the study is normal. In contrast, functional stroke outcome varies dramatically among patients and is affected by the size, location and subtype of stroke. Prognosis is usually determined after diagnostic tests, including brain imaging, are performed over the course of the patient?s hospital stay. However, decisions regarding the risk/benefit profile of acute treatment options and resource allocation occur in the first hours after stroke. The costs of stroke, to the patient as well as to the healthcare system, are potentially modifiable if early diagnostic studies are able to predict outcome and directly impact on acute management. In a study that takes only minutes, new, ultra-fast multidector CT (MDCT) scanners enable the emergency evaluation of stroke patients, combining non-contrast brain computerized tomography (CT), computed tomographic angiography of the head and neck (CTA), and computed tomographic brain tissue perfusion (CTP). Coupled with careful clinical assessment, this "next generation" imaging technology has the potential to identify both the vascular cause of the stroke and the precise brain regions at risk, establishing the prognosis within an hour of the patient?s arrival in the emergency ward. The proposed research seeks to better define the characteristics affecting the clinical and financial costs of specific subtypes of strokes and to test this new imaging technology in the emergency setting for its ability to predict long term patient outcome. To this end, the applicant has developed three specific aims. First, investigators will determine the test performance characteristics (sensitivity, specificity) of acute ischemic stroke neuroimaging with MDCT in predicting those patients most likely to have poor outcome using the final clinical diagnosis based on the well known TOAST (Trial of Organon 10172 in Acute Stroke Treatment) criteria as the gold standard. Second, investigators will determine whether MDCT is superior to conventional non-contrast brain computerized tomography alone in predicting functional outcome from stroke. Third, a predictive model will be developed of stroke cost based on the contributions of subtype of strokes, treatments, co-morbidities, stroke size and location. The economic model will establish a means to measure the cost effectiveness of innovative stroke management, diagnostic testing, and therapies. This research will allow develop of economic models based on the costs and outcomes of different subtype of strokes. It will enable early prognostication of functional outcome, improving the clinician?s ability to make difficult treatment decisions in the hours after stroke onset, and serve as a guide for the allocation of health care resources.